// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/browser/notifications/notification_id_generator.h"

#include <sstream>

#include "base/base64.h"
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/sha1.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/utf_string_conversions.h"
#include "build/build_config.h"
#include "content/public/browser/browser_context.h"
#include "url/gurl.h"

namespace content {
namespace {

    const char kPersistentNotificationPrefix[] = "p:";
    const char kNonPersistentNotificationPrefix[] = "n:";

    const char kSeparator = '#';

    // Computes a hash based on the path in which the |browser_context| is stored.
    // Since we only store the hash, SHA-1 is used to make the probability of
    // collisions negligible.
    std::string ComputeBrowserContextHash(BrowserContext* browser_context)
    {
        const base::FilePath path = browser_context->GetPath();

#if defined(OS_WIN)
        std::string path_hash = base::SHA1HashString(base::WideToUTF8(path.value()));
#else
        std::string path_hash = base::SHA1HashString(path.value());
#endif

        return base::HexEncode(path_hash.c_str(), path_hash.length());
    }

} // namespace

NotificationIdGenerator::NotificationIdGenerator(
    BrowserContext* browser_context)
    : browser_context_(browser_context)
{
}

NotificationIdGenerator::~NotificationIdGenerator() { }

// static
bool NotificationIdGenerator::IsPersistentNotification(
    const base::StringPiece& notification_id)
{
    return notification_id.starts_with(kPersistentNotificationPrefix);
}

// static
bool NotificationIdGenerator::IsNonPersistentNotification(
    const base::StringPiece& notification_id)
{
    return notification_id.starts_with(kNonPersistentNotificationPrefix);
}

std::string NotificationIdGenerator::GenerateForPersistentNotification(
    const GURL& origin,
    const std::string& tag,
    int64_t persistent_notification_id) const
{
    DCHECK(origin.is_valid());
    DCHECK_EQ(origin, origin.GetOrigin());

    std::stringstream stream;

    stream << kPersistentNotificationPrefix;
    stream << ComputeBrowserContextHash(browser_context_);
    stream << base::IntToString(browser_context_->IsOffTheRecord());
    stream << origin;

    stream << base::IntToString(!tag.empty());
    if (tag.size())
        stream << tag;
    else
        stream << base::Int64ToString(persistent_notification_id);

    return stream.str();
}

std::string NotificationIdGenerator::GenerateForNonPersistentNotification(
    const GURL& origin,
    const std::string& tag,
    int non_persistent_notification_id,
    int render_process_id) const
{
    DCHECK(origin.is_valid());
    DCHECK_EQ(origin, origin.GetOrigin());

    std::stringstream stream;

    stream << kNonPersistentNotificationPrefix;
    stream << ComputeBrowserContextHash(browser_context_);
    stream << base::IntToString(browser_context_->IsOffTheRecord());
    stream << origin;

    stream << base::IntToString(!tag.empty());
    if (tag.empty()) {
        stream << base::IntToString(render_process_id);
        stream << kSeparator;

        stream << base::IntToString(non_persistent_notification_id);
    } else {
        stream << tag;
    }

    return stream.str();
}

} // namespace content
